A230806 The smallest of 4 consecutive palindromic numbers that are all primes.

1878781, 11782828711, 13828882831, 33694849633, 36331813363, 76093839067, 93121812139, 1018278728101, 1101228221011, 1200528250021, 1237788877321, 1296978796921, 1318608068131, 1449108019441, 1477968697741, 1608678768061, 1713708073171, 1792308032971

Offset

1,1

Comments

There cannot be 5 consecutive palindromic numbers that are all primes. The central digit of all numbers in the sequence will be 8.

Links

Shyam Sunder Gupta, Table of n, a(n) for n = 1..2166

Example

1878781 is in the sequence because 1878781, 1879781, 1880881 and 1881881 are consecutive palindromic numbers that are all primes.

Mathematica

a = {}; m = 0; Do[z = n*10^(IntegerLength[n] - 1) + FromDigits@Rest@Reverse@IntegerDigits[n]; If[PrimeQ[z], m = m + 1; If[m == 1, z1 = z]; If[m == 4, AppendTo[a, z1]], m = 0], {n, 1, 1000000000}]

Crossrefs

Cf. A000040, A002113, A002385, A032595.

Sequence in context: A251008 A064820 A032595 * A032596 A032597 A203794

Adjacent sequences: A230803 A230804 A230805 * A230807 A230808 A230809

Keyword

nonn,base

Author

Shyam Sunder Gupta, Oct 30 2013

Status

approved